Lizards squirt blood from their eyeballs

If you were to poke a Texas horned lizard, it wouldn't bite you. It would wait until the pressure in its head built to a breaking point, then rupture the thin capillaries in its eyelids to spray you with a direct stream of its own blood.

The lizard isn't just bleeding; it's aiming. These squirts can travel five feet, hitting a predator square in the face with a liquid that tastes like chemical poison.

This isn't a random biological malfunction. To pull this off, the lizard restricts the blood leaving its head while its heart keeps pumping it in. The resulting pressure swell is so intense that the vessels around the eye socket simply burst on command.

While the sight of a bleeding eye is enough to startle a human, the real weapon is a cocktail of toxins. The lizard eats almost nothing but harvester ants, which are loaded with venom. It stores these alkaloid compounds in its system, turning its own blood into a foul-tasting deterrent specifically designed to trigger the gag reflex of a canine.

A coyote or bobcat that gets hit will spend the next fifteen minutes pawing at its mouth, trying to shake the taste. Yet, curiously, this biological warfare doesn't work on birds. Hawks and roadrunners are immune to the blood’s chemical bitterness, so against them, the lizard stays silent and relies on its camouflage.

This means the lizard has to identify exactly what is hunting it before choosing which defense to deploy. It must look its killer in the eye to decide if it’s worth exploding its own face.

The lizard can lose as much as a third of its total blood supply in one sitting without any long-term health effects. It simply goes back to eating ants and waits for its ocular cannons to reload.

Even more strange is that the lizard has a "third eye" on the top of its head, a translucent scale called a parietal eye that senses light and shadows, effectively watching the sky while its primary eyes are busy drowning a fox in red.